package info.bliki.wiki.filter;

import java.io.IOException;

import info.bliki.htmlcleaner.Utils;

/**
 * Some helper methods for encoding strings to HTML, URL or local files system
 * names
 * 
 */
public class Encoder {

	final static String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05", "%06", "%07", "%08", "%09", "%0A", "%0B", "%0C", "%0D",
			"%0E", "%0F", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17", "%18", "%19", "%1A", "%1B", "%1C", "%1D", "%1E", "%1F",
			"%20", "%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29", "%2A", "%2B", "%2C", "%2D", "%2E", "%2F", "%30", "%31",
			"%32", "%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3A", "%3B", "%3C", "%3D", "%3E", "%3F", "%40", "%41", "%42", "%43",
			"%44", "%45", "%46", "%47", "%48", "%49", "%4A", "%4B", "%4C", "%4D", "%4E", "%4F", "%50", "%51", "%52", "%53", "%54", "%55",
			"%56", "%57", "%58", "%59", "%5A", "%5B", "%5C", "%5D", "%5E", "%5F", "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67",
			"%68", "%69", "%6A", "%6B", "%6C", "%6D", "%6E", "%6F", "%70", "%71", "%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79",
			"%7A", "%7B", "%7C", "%7D", "%7E", "%7F", "%80", "%81", "%82", "%83", "%84", "%85", "%86", "%87", "%88", "%89", "%8A", "%8B",
			"%8C", "%8D", "%8E", "%8F", "%90", "%91", "%92", "%93", "%94", "%95", "%96", "%97", "%98", "%99", "%9A", "%9B", "%9C", "%9D",
			"%9E", "%9F", "%A0", "%A1", "%A2", "%A3", "%A4", "%A5", "%A6", "%A7", "%A8", "%A9", "%AA", "%AB", "%AC", "%AD", "%AE", "%AF",
			"%B0", "%B1", "%B2", "%B3", "%B4", "%B5", "%B6", "%B7", "%B8", "%B9", "%BA", "%BB", "%BC", "%BD", "%BE", "%BF", "%C0", "%C1",
			"%C2", "%C3", "%C4", "%C5", "%C6", "%C7", "%C8", "%C9", "%CA", "%CB", "%CC", "%CD", "%CE", "%CF", "%D0", "%D1", "%D2", "%D3",
			"%D4", "%D5", "%D6", "%D7", "%D8", "%D9", "%DA", "%DB", "%DC", "%DD", "%DE", "%DF", "%E0", "%E1", "%E2", "%E3", "%E4", "%E5",
			"%E6", "%E7", "%E8", "%E9", "%EA", "%EB", "%EC", "%ED", "%EE", "%EF", "%F0", "%F1", "%F2", "%F3", "%F4", "%F5", "%F6", "%F7",
			"%F8", "%F9", "%FA", "%FB", "%FC", "%FD", "%FE", "%FF" };

	final static String[] hex1 = { ".00", ".01", ".02", ".03", ".04", ".05", ".06", ".07", ".08", ".09", ".0A", ".0B", ".0C", ".0D",
			".0E", ".0F", ".10", ".11", ".12", ".13", ".14", ".15", ".16", ".17", ".18", ".19", ".1A", ".1B", ".1C", ".1D", ".1E", ".1F",
			".20", ".21", ".22", ".23", ".24", ".25", ".26", ".27", ".28", ".29", ".2A", ".2B", ".2C", ".2D", ".2E", ".2F", ".30", ".31",
			".32", ".33", ".34", ".35", ".36", ".37", ".38", ".39", ".3A", ".3B", ".3C", ".3D", ".3E", ".3F", ".40", ".41", ".42", ".43",
			".44", ".45", ".46", ".47", ".48", ".49", ".4A", ".4B", ".4C", ".4D", ".4E", ".4F", ".50", ".51", ".52", ".53", ".54", ".55",
			".56", ".57", ".58", ".59", ".5A", ".5B", ".5C", ".5D", ".5E", ".5F", ".60", ".61", ".62", ".63", ".64", ".65", ".66", ".67",
			".68", ".69", ".6A", ".6B", ".6C", ".6D", ".6E", ".6F", ".70", ".71", ".72", ".73", ".74", ".75", ".76", ".77", ".78", ".79",
			".7A", ".7B", ".7C", ".7D", ".7E", ".7F", ".80", ".81", ".82", ".83", ".84", ".85", ".86", ".87", ".88", ".89", ".8A", ".8B",
			".8C", ".8D", ".8E", ".8F", ".90", ".91", ".92", ".93", ".94", ".95", ".96", ".97", ".98", ".99", ".9A", ".9B", ".9C", ".9D",
			".9E", ".9F", ".A0", ".A1", ".A2", ".A3", ".A4", ".A5", ".A6", ".A7", ".A8", ".A9", ".AA", ".AB", ".AC", ".AD", ".AE", ".AF",
			".B0", ".B1", ".B2", ".B3", ".B4", ".B5", ".B6", ".B7", ".B8", ".B9", ".BA", ".BB", ".BC", ".BD", ".BE", ".BF", ".C0", ".C1",
			".C2", ".C3", ".C4", ".C5", ".C6", ".C7", ".C8", ".C9", ".CA", ".CB", ".CC", ".CD", ".CE", ".CF", ".D0", ".D1", ".D2", ".D3",
			".D4", ".D5", ".D6", ".D7", ".D8", ".D9", ".DA", ".DB", ".DC", ".DD", ".DE", ".DF", ".E0", ".E1", ".E2", ".E3", ".E4", ".E5",
			".E6", ".E7", ".E8", ".E9", ".EA", ".EB", ".EC", ".ED", ".EE", ".EF", ".F0", ".F1", ".F2", ".F3", ".F4", ".F5", ".F6", ".F7",
			".F8", ".F9", ".FA", ".FB", ".FC", ".FD", ".FE", ".FF" };

	final static String[] hex2 = { "'00", "'01", "'02", "'03", "'04", "'05", "'06", "'07", "'08", "'09", "'0A", "'0B", "'0C", "'0D",
			"'0E", "'0F", "'10", "'11", "'12", "'13", "'14", "'15", "'16", "'17", "'18", "'19", "'1A", "'1B", "'1C", "'1D", "'1E", "'1F",
			"'20", "'21", "'22", "'23", "'24", "'25", "'26", "'27", "'28", "'29", "'2A", "'2B", "'2C", "'2D", "'2E", "'2F", "'30", "'31",
			"'32", "'33", "'34", "'35", "'36", "'37", "'38", "'39", "'3A", "'3B", "'3C", "'3D", "'3E", "'3F", "'40", "'41", "'42", "'43",
			"'44", "'45", "'46", "'47", "'48", "'49", "'4A", "'4B", "'4C", "'4D", "'4E", "'4F", "'50", "'51", "'52", "'53", "'54", "'55",
			"'56", "'57", "'58", "'59", "'5A", "'5B", "'5C", "'5D", "'5E", "'5F", "'60", "'61", "'62", "'63", "'64", "'65", "'66", "'67",
			"'68", "'69", "'6A", "'6B", "'6C", "'6D", "'6E", "'6F", "'70", "'71", "'72", "'73", "'74", "'75", "'76", "'77", "'78", "'79",
			"'7A", "'7B", "'7C", "'7D", "'7E", "'7F", "'80", "'81", "'82", "'83", "'84", "'85", "'86", "'87", "'88", "'89", "'8A", "'8B",
			"'8C", "'8D", "'8E", "'8F", "'90", "'91", "'92", "'93", "'94", "'95", "'96", "'97", "'98", "'99", "'9A", "'9B", "'9C", "'9D",
			"'9E", "'9F", "'A0", "'A1", "'A2", "'A3", "'A4", "'A5", "'A6", "'A7", "'A8", "'A9", "'AA", "'AB", "'AC", "'AD", "'AE", "'AF",
			"'B0", "'B1", "'B2", "'B3", "'B4", "'B5", "'B6", "'B7", "'B8", "'B9", "'BA", "'BB", "'BC", "'BD", "'BE", "'BF", "'C0", "'C1",
			"'C2", "'C3", "'C4", "'C5", "'C6", "'C7", "'C8", "'C9", "'CA", "'CB", "'CC", "'CD", "'CE", "'CF", "'D0", "'D1", "'D2", "'D3",
			"'D4", "'D5", "'D6", "'D7", "'D8", "'D9", "'DA", "'DB", "'DC", "'DD", "'DE", "'DF", "'E0", "'E1", "'E2", "'E3", "'E4", "'E5",
			"'E6", "'E7", "'E8", "'E9", "'EA", "'EB", "'EC", "'ED", "'EE", "'EF", "'F0", "'F1", "'F2", "'F3", "'F4", "'F5", "'F6", "'F7",
			"'F8", "'F9", "'FA", "'FB", "'FC", "'FD", "'FE", "'FF" };

	public static String toEntity(int c) {
		return "&#" + c + ";";
	}

	public static char toChar(String number) {
		return (char) Integer.decode(number.substring(1)).intValue();
	}

/**
	 * Encode a string to the "x-www-form-urlencoded" form, enhanced with the
	 * UTF-8-in-URL proposal. This is what happens: See
	 * http://www.w3.org/International/URLUTF8Encoder.java ) Exception: a ' '
	 * (space) will be replaced by a '_' (underscore) not '+' (plus); a '#' remain the same.
	 * 
	 * <ul>
	 * <li>
	 * <p>
	 * The ASCII characters 'a' through 'z', 'A' through 'Z', and '0' through '9'
	 * remain the same.
	 * 
	 * <li>
	 * <p>
	 * The unreserved characters - _ . ! ~ * ' ( ) / remain the same.
	 * 
	 * <li>
	 * <p>
	 * The '#' character remains the same.
	 * 
	 * <li>
	 * <p>
	 * The space character ' ' is converted into a underscore sign '_' (not a plus
	 * sign '+'!).
	 * 
	 * <li>
	 * <p>
	 * All other ASCII characters are converted into the 3-character string "%xy",
	 * where xy is the two-digit hexadecimal representation of the character code
	 * 
	 * <li>
	 * <p>
	 * All non-ASCII characters are encoded in two steps: first to a sequence of 2
	 * or 3 bytes, using the UTF-8 algorithm; secondly each of these bytes is
	 * encoded as ".xx".
	 * </ul>
	 * 
	 * @param s
	 *          The string to be encoded
	 * @return The encoded string
	 */
	public static String encodeUrl(String s) {
		int len = s.length();
		if (len == 0) {
			return "";
		}
		StringBuilder sbuf = new StringBuilder(len + len / 10);
		for (int i = 0; i < len; i++) {
			int ch = s.charAt(i);
			encodeUrl(sbuf, ch);
		}
		return sbuf.toString();
	}

	/**
	 * Encode character for webbrowsers
	 */
	private static void encodeUrl(StringBuilder sbuf, int ch) {
		if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
			sbuf.append((char) ch);
		} else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
			sbuf.append((char) ch);
		} else if ('0' <= ch && ch <= '9') { // '0'..'9'
			sbuf.append((char) ch);
		} else if (ch == ' ') { // space
			// sbuf.append('+');
			sbuf.append('_'); // special for wiki syntax !
		} else if (ch == '#') {
			sbuf.append('#');
		} else if (ch == '-' || ch == '_' || ch == '/' || ch == '.' || ch == ':' || ch == '!' || ch == '~' || ch == '\'' || ch == '('
				|| ch == ')') {
			sbuf.append((char) ch);
		} else if (ch <= 0x007f) { // other ASCII
			sbuf.append(hex[ch]);
		} else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
			sbuf.append(hex[0xc0 | (ch >> 6)]);
			sbuf.append(hex[0x80 | (ch & 0x3F)]);
		} else { // 0x7FF < ch <= 0xFFFF
			sbuf.append(hex[0xe0 | (ch >> 12)]);
			sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]);
			sbuf.append(hex[0x80 | (ch & 0x3F)]);
		}
	}

/**
	 * Encode a string to the "x-www-form-urlencoded" form, enhanced with the
	 * UTF-8-in-URL proposal. This is what happens: 8see
	 * http://www.w3.org/International/URLUTF8Encoder.java ) Exception: a ' '
	 * (space) will be replaced by a '_' (underscore) not '+' (plus)
	 * 
	 * <ul>
	 * <li>
	 * <p>
	 * The ASCII characters 'a' through 'z', 'A' through 'Z', and '0' through '9'
	 * remain the same.
	 * 
	 * <li>
	 * <p>
	 * The unreserved characters - _ . ! ~ * ' ( ) / remain the same.
	 * 
	 * <li>
	 * <p>
	 * The space character ' ' is converted into a underscore sign '_' (not a plus
	 * sign '+').
	 * 
	 * <li>
	 * <p>
	 * All other ASCII characters are converted into the 3-character string "%xy",
	 * where xy is the two-digit hexadecimal representation of the character code
	 * 
	 * <li>
	 * <p>
	 * All non-ASCII characters are encoded in two steps: first to a sequence of 2
	 * or 3 bytes, using the UTF-8 algorithm; secondly each of these bytes is
	 * encoded as ".xx".
	 * </ul>
	 * 
	 * @param s
	 *          The string to be encoded
	 * @return The encoded string
	 */
	public static String encodeDotUrl(String s) {
		int len = s.length();
		if (len == 0) {
			return "";
		}
		StringBuilder sbuf = new StringBuilder(len + len / 10);
		for (int i = 0; i < len; i++) {
			int ch = s.charAt(i);
			encodeDotUrl(sbuf, ch);
		}
		return sbuf.toString();
	}

	/**
	 * Encode character for webbrowsers
	 */
	private static void encodeDotUrl(StringBuilder sbuf, int ch) {
		if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
			sbuf.append((char) ch);
		} else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
			sbuf.append((char) ch);
		} else if ('0' <= ch && ch <= '9') { // '0'..'9'
			sbuf.append((char) ch);
		} else if (ch == ' ') { // space
			sbuf.append('_'); // special for wiki syntax !
		} else if (ch == '-' || ch == '_' || ch == '.' || ch == ':') {
			sbuf.append((char) ch);
		} else if (ch <= 0x007f) { // other ASCII
			sbuf.append(hex1[ch]);
		} else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
			sbuf.append(hex1[0xc0 | (ch >> 6)]);
			sbuf.append(hex1[0x80 | (ch & 0x3F)]);
		} else { // 0x7FF < ch <= 0xFFFF
			sbuf.append(hex1[0xe0 | (ch >> 12)]);
			sbuf.append(hex1[0x80 | ((ch >> 6) & 0x3F)]);
			sbuf.append(hex1[0x80 | (ch & 0x3F)]);
		}
	}

	/**
	 * Encode character for local file system
	 * 
	 * @param sbuf
	 * @param ch
	 */
	private static void encodeLocalUrl(StringBuilder sbuf, int ch) {
		if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
			sbuf.append((char) ch);
		} else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
			sbuf.append((char) ch);
		} else if ('0' <= ch && ch <= '9') { // '0'..'9'
			sbuf.append((char) ch);
		} else if (ch == ' ') { // space
			// sbuf.append('+');
			sbuf.append('_'); // special for wiki syntax !
		} else if (ch == '-' || ch == '_' || ch == '/' || ch == '!' || ch == '~' || ch == '(' || ch == ')') {
			sbuf.append((char) ch);
			// } else if (ch == ':') {
			// sbuf.append('/');
		} else if (ch <= 0x007f) { // other ASCII
			sbuf.append(hex2[ch]);
		} else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
			sbuf.append(hex2[0xc0 | (ch >> 6)]);
			sbuf.append(hex2[0x80 | (ch & 0x3F)]);
		} else { // 0x7FF < ch <= 0xFFFF
			sbuf.append(hex2[0xe0 | (ch >> 12)]);
			sbuf.append(hex2[0x80 | ((ch >> 6) & 0x3F)]);
			sbuf.append(hex2[0x80 | (ch & 0x3F)]);
		}
	}

	/**
	 * Encode the <i>wiki links title</i> into a URL for HTML hyperlinks (i.e.
	 * create the <i>href</i> attribute representation for the <i>a</i> tag). To
	 * get the behavior of the MediaWiki software, which is configured to convert
	 * the first letter to upper case, the <code>firstCharacterAsUpperCase</code>
	 * parameters must be set to <code>true</code>.
	 * 
	 * @param wikiTitle
	 *          the raw wiki title
	 * @param firstCharacterAsUpperCase
	 *          if <code>true</code> convert the first of the title to upper case
	 * @return the encoded wiki title
	 */
	public static String encodeTitleToUrl(String wikiTitle, boolean firstCharacterAsUpperCase) {
		int len = wikiTitle.length();
		if (len == 0) {
			return "";
		}
		for (int j = len - 1; j > 0; j--) {
			if (Character.isWhitespace(wikiTitle.charAt(j))) {
				continue;
			}
			len = j + 1;
			break;
		}

		boolean whiteSpace = true;
		StringBuilder buffer = new StringBuilder(len + len / 10);
		char ch;
		for (int i = 0; i < len; i++) {
			ch = wikiTitle.charAt(i);
			if (whiteSpace && Character.isWhitespace(ch)) {
				continue;
			}
			if (whiteSpace) {
				whiteSpace = false;
				if (firstCharacterAsUpperCase) {
					Encoder.encodeUrl(buffer, Character.toUpperCase(ch));
					continue;
				}
			}
			Encoder.encodeUrl(buffer, ch);
		}
		return buffer.toString();
	}

	public static String encodeTitleDotUrl(String wikiTitle, boolean firstCharacterAsUpperCase) {
		int len = wikiTitle.length();
		if (len == 0) {
			return "";
		}
		for (int j = len - 1; j > 0; j--) {
			if (Character.isWhitespace(wikiTitle.charAt(j))) {
				continue;
			}
			len = j + 1;
			break;
		}

		boolean whiteSpace = true;
		StringBuilder buffer = new StringBuilder(len + len / 10);
		char ch;
		for (int i = 0; i < len; i++) {
			ch = wikiTitle.charAt(i);
			if (whiteSpace && Character.isWhitespace(ch)) {
				continue;
			}
			if (whiteSpace) {
				whiteSpace = false;
				if (firstCharacterAsUpperCase) {
					Encoder.encodeDotUrl(buffer, Character.toUpperCase(ch));
					continue;
				}
			}
			Encoder.encodeDotUrl(buffer, ch);
		}
		return buffer.toString();
	}

	/**
	 * Encode name for local file system
	 * 
	 */
	public static String encodeTitleLocalUrl(String wikiTitle) {
		int len = wikiTitle.length();
		if (len == 0) {
			return "";
		}
		for (int j = len - 1; j > 0; j--) {
			if (Character.isWhitespace(wikiTitle.charAt(j))) {
				continue;
			}
			len = j + 1;
			break;
		}

		boolean colon = false;
		boolean whiteSpace = true;
		StringBuilder buffer = new StringBuilder(len + len / 10);
		char ch;
		for (int i = 0; i < len; i++) {
			ch = wikiTitle.charAt(i);
			if (whiteSpace && Character.isWhitespace(ch)) {
				continue;
			}
			if (whiteSpace) {
				whiteSpace = false;
				Encoder.encodeLocalUrl(buffer, Character.toUpperCase(ch));
				continue;
			}
			if (colon) {
				colon = false;
				Encoder.encodeLocalUrl(buffer, Character.toUpperCase(ch));
				continue;
			}
			Encoder.encodeLocalUrl(buffer, ch);
		}
		return buffer.toString();
	}

	/**
	 * copy the text in the resulting buffer and escape special html characters
	 * (&lt; &gt; &#34; ( &quot; ) &amp; &#39;)
	 * 
	 * @param buffer
	 *          add converted text into the resulting buffer
	 */
	public static void encodeHtml(String text, StringBuilder buffer) {
		if (text.length() == 0) {
			return;
		}
		try {
			Utils.escapeXmlToBuffer(text, buffer, true, true, true);
		} catch (IOException e) {
			buffer.append("Error in encodeHtml: IOException");
		}
		//	    
		// final int len = text.length();
		// if (len == 0) {
		// return;
		// }
		// int currentIndex = 0;
		// int lastIndex = currentIndex;
		// while (currentIndex < len) {
		// switch (text.charAt(currentIndex++)) {
		// case '\r': //
		// if (lastIndex < (currentIndex - 1)) {
		// buffer.append(text.substring(lastIndex, currentIndex - 1));
		// lastIndex = currentIndex;
		// }
		// break;
		// case '<': // special html escape character
		// if (lastIndex < (currentIndex - 1)) {
		// buffer.append(text.substring(lastIndex, currentIndex - 1));
		// lastIndex = currentIndex;
		// }
		// buffer.append("&lt;");
		// break;
		// case '>': // special html escape character
		// if (lastIndex < (currentIndex - 1)) {
		// buffer.append(text.substring(lastIndex, currentIndex - 1));
		// lastIndex = currentIndex;
		// } else {
		// lastIndex++;
		// }
		// buffer.append("&gt;");
		// break;
		// case '&': // special html escape character
		// if (lastIndex < (currentIndex - 1)) {
		// buffer.append(text.substring(lastIndex, currentIndex - 1));
		// lastIndex = currentIndex;
		// } else {
		// lastIndex++;
		// }
		// buffer.append("&amp;");
		// break;
		// case '\'': // special html escape character
		// if (lastIndex < (currentIndex - 1)) {
		// buffer.append(text.substring(lastIndex, currentIndex - 1));
		// lastIndex = currentIndex;
		// } else {
		// lastIndex++;
		// }
		// buffer.append("&#39;");
		// break;
		// case '\"': // special html escape character
		// if (lastIndex < (currentIndex - 1)) {
		// buffer.append(text.substring(lastIndex, currentIndex - 1));
		// lastIndex = currentIndex;
		// } else {
		// lastIndex++;
		// }
		// buffer.append("&#34;");
		// break;
		// }
		// }
		// if (lastIndex < currentIndex) {
		// buffer.append(text.substring(lastIndex, currentIndex));
		// }
	}

	public static String encodeHtml(String text) {
		int len = text.length();
		if (len == 0) {
			return "";
		}
		StringBuilder buffer = new StringBuilder(len + len / 10);
		encodeHtml(text, buffer);
		return buffer.toString();
	}

	/**
	 * Determines if the specified character may be part of a url
	 */
	public final static boolean isUrlIdentifierPart(char ch) {
		if (Character.isLetterOrDigit(ch)) {
			return true;
		}
		final String test = "-_.!~*';/?:@#&=+$,%";
		return test.indexOf(ch) != (-1);
	}

	/**
	 * Determines if the specified character may be part of a wiki plugin
	 * identifier as other than the first character
	 */
	public final static boolean isWikiPluginIdentifierPart(char ch) {
		return Character.isLetterOrDigit(ch) || (ch == '_');
	}

	/**
	 * Determines if the specified character may be part the first character of a
	 * wiki plugin identifier
	 */
	public final static boolean isWikiPluginIdentifierStart(char ch) {
		return Character.isLetter(ch);
	}
}